Nature Notes: A little bird with a sizable job

We have a summer resident in Minnesota worth introducing again.

Banding records tell us that the ruby-throated hummingbird — the only one of its species to nest east of the Rockies — may well return next summer, and perhaps for several more.

During courtship, the female ruby-throat sits quietly on a perch while the male displays in a pendulum dance. He flies in a wide arc and buzzes loudly with each dip. The female shows no preference for a particular male until just before laying eggs. Observers agree that the male takes no part in nesting activities and is even suspected of polygamy.

To build a nest, the female chooses a limb or twig positioned 10 to 20 feet off the ground and sheltered by overshadowing leaves. She then collects silky or downy fibers and binds them together with spider webs. The nest, 2 inches or fewer in diameter, is then covered with bits of lichen.

Nest building takes about a week. The finished nest looks like a small knot covered with tree lichens. The two white eggs are laid one day apart and are about the size of large peas. The female incubates the eggs, which hatch in about 14 to 16 days.

The newly born young stay in the nest for about 20 days. Fledglings stay with their mother another week or so. Nesting takes place from June into July. Only one brood is raised each year.

Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.